Hydro One

aid: hydro-one
url: https://raw.githubusercontent.com/api-evangelist/hydro-one/refs/heads/main/apis.yml
name: Hydro One
kind: company
description: 'Hydro One Limited (TSX: H) is Canada''s largest electricity transmission and distribution service provider,
  transmitting and distributing electricity across Ontario — the province the company describes as "home to 38 per cent of
  Canada''s population." It sits in the regulated wires tier of the value chain: it owns and operates the provincial transmission
  grid and a rural/regional distribution network serving roughly 1.5 million customers, while the Ontario market itself is
  operated by the IESO and rates are set by the Ontario Energy Board. Its API posture is defined entirely by regulation, not
  by product. Ontario Regulation 633/21 (Energy Data, under the Electricity Act, 1998) compels Ontario electricity and natural
  gas distributors to implement Green Button Download My Data (DMD) and Connect My Data (CMD) and to have those implementations
  certified by the Green Button Alliance. Hydro One publishes DMD as an authenticated XML export inside My Account, runs a
  live Green Button CMD OAuth 2.0 authorization surface at www.hydroone.com/green-button-cmd-home, and operates a published
  third-party vendor onboarding form and terms and conditions — but the CMD resource base URI, client credentials, and test
  accounts are issued privately during onboarding and are not published anywhere. There is no developer subdomain, no OpenAPI
  or Swagger definition, and no self-serve signup. The split is the finding: consumer energy data is available through a real,
  standards-based, mandated API that a developer can only reach by application and 90-day connectivity testing, while open
  grid and market data is entirely absent — Hydro One publishes no open data portal and no documented public system or outage
  API, leaving Ontario market data to the IESO.'
accessModel:
  pricing: free
  onboarding: application-approval
  trial: false
  try_now: false
  public: false
  label: Free · Application and approval required
  confidence: high
  source:
  - documentation
  - terms
  generated: '2026-07-27'
  method: manual
image: https://www.hydroone.com/Style%20Library/H1/images/logo.svg
tags:
- Energy
- Canada
- Utilities
- Electricity
- Grid
- Smart Metering
- Green Button
- Energy Data
- Transmission
- Distribution
created: '2026-07-27'
modified: '2026-07-27'
specificationVersion: '0.23'
apis:
- aid: hydro-one:hydro-one-green-button-connect-my-data
  name: Hydro One Green Button Connect My Data (CMD)
  description: Hydro One's Green Button Connect My Data implementation, mandated by Ontario Regulation 633/21. A registered
    third-party vendor obtains an OAuth 2.0 authorization code after the customer authenticates with Hydro One and consents,
    then retrieves that customer's electricity usage and billing data as NAESB ESPI XML. The live authorization surface at
    https://www.hydroone.com/green-button-cmd-home was observed serving a real Green Button authorization request carrying
    ESPI function-block scope syntax (FB=1_3_4_5_13_15_16_31_37_39_51_53_54_55_56_57_58_59_60_64_65;historyLength=32148000)
    for a third-party redirect URI. Hydro One does not publish the CMD resource base URI, an OpenAPI definition, or any endpoint
    reference — Client ID, Client Secret, test accounts, and URI(s) are issued privately during vendor onboarding, followed
    by a 90-day connectivity test and an exchange of RSA 2048-bit certificates over TLS.
  humanURL: https://www.hydroone.com/saving-money-and-energy/green-button/third-party-apps
  tags:
  - Green Button
  - Connect My Data
  - ESPI
  - Energy Data
  - Authentication
  - Consumer Data
  tags_raw:
  - Green Button
  - Connect My Data
  - ESPI
  - Energy Data
  - OAuth2
  - Consumer Data
  properties:
  - type: Documentation
    url: https://www.hydroone.com/saving-money-and-energy/green-button
  - type: Documentation
    url: https://www.hydroone.com/saving-money-and-energy/green-button/third-party-apps
  - type: TermsOfService
    url: https://www.hydroone.com/saving-money-and-energy/green-button/third-party-terms-and-conditions
  - type: SignUp
    url: https://www.hydroone.com/saving-money-and-energy/green-button/third-party-onboarding-form
  - type: GettingStarted
    url: https://www.hydroone.com/saving-money-and-energy/green-button/third-party-apps
  - type: Authentication
    url: https://www.hydroone.com/green-button-cmd-home
  - type: Authentication
    url: authentication/hydro-one-authentication.yml
  - type: OAuthScopes
    url: scopes/hydro-one-scopes.yml
  - type: Sandbox
    url: sandbox/hydro-one-sandbox.yml
  - type: Regulation
    url: https://www.ontario.ca/laws/regulation/210633
  - type: Standard
    url: https://www.greenbuttonalliance.org/
  - type: Regulator
    url: https://www.oeb.ca/consumer-information-and-protection/green-button
common:
- type: DomainSecurity
  url: security/hydro-one-domain-security.yml
- type: Authentication
  url: authentication/hydro-one-authentication.yml
- type: OAuthScopes
  url: scopes/hydro-one-scopes.yml
- type: Conventions
  url: conventions/hydro-one-conventions.yml
- type: Conformance
  url: conformance/hydro-one-conformance.yml
- type: Lifecycle
  url: lifecycle/hydro-one-lifecycle.yml
- type: Sandbox
  url: sandbox/hydro-one-sandbox.yml
- type: LLMsTxt
  url: llms/hydro-one-llms.txt
- type: Website
  url: https://www.hydroone.com/
- type: About
  url: https://www.hydroone.com/about
- type: Documentation
  url: https://www.hydroone.com/saving-money-and-energy/green-button
- type: GettingStarted
  url: https://www.hydroone.com/saving-money-and-energy/green-button/third-party-apps
- type: SignUp
  url: https://www.hydroone.com/saving-money-and-energy/green-button/third-party-onboarding-form
- type: TermsOfService
  url: https://www.hydroone.com/saving-money-and-energy/green-button/third-party-terms-and-conditions
- type: TermsOfUse
  url: https://www.hydroone.com/terms-of-use
- type: PrivacyPolicy
  url: https://www.hydroone.com/privacy
- type: Support
  url: https://www.hydroone.com/contact
- type: News
  url: https://www.hydroone.com/newsroom
- type: LinkedIn
  url: https://www.linkedin.com/company/hydro-one
- type: Regulator
  url: https://www.oeb.ca/consumer-information-and-protection/green-button
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com